A communication system can be seen as a facility that enables communication sessions between two or more entities such as one or more communication devices and/or other nodes associated with the communication system. A communication system typically operates in accordance with a given standard or specification setting out what the various entities associated with the communication system are permitted to do and how that should be achieved. A standard or specification may define a specific set of rules, such as communication protocols and/or parameters, on which connections between the entities can be based.
Wireless communication systems include various cellular or otherwise mobile communication systems using radio frequencies for sending voice or data between stations, for example between a communication device and a transceiver network element. Examples of wireless communication systems may comprise public land mobile network (PLMN), such as global system for mobile communication (GSM), the general packet radio service (GPRS) and the universal mobile telecommunications system (UMTS). A mobile communication network may logically be divided into a radio access network (RAN) and a core network (CN). The core network entities typically include various control entities and gateways for enabling communication via a number of radio access networks and also for interfacing a single communication system with one or more communication systems, such as with other wireless systems, such as a wireless Internet Protocol (IP) network, and/or fixed line communication systems. Examples of radio access networks may comprise the UMTS terrestrial radio access network (UTRAN) and the GSM/EDGE radio access network (GERAN).
Subscribers, such as the users or end-users, to a communication system may be offered and provided numerous services, such as calls, data communication or multimedia services or simply an access to a network, such as the Internet. Servers may be used in provision of the services and may be operated by an operator of a network or by an external service provider. For example, the wireless application protocol (WAP) provides mobile communication devices services over wireless communication networks. For example, a mobile communication device may allow a user thereof to browse the Internet using the WAP.
Said services may comprise conferencing services, such as multiparty conferencing, for example so-called direct voice communication services. The direct voice communication service may allow users to engage in immediate communication with one or more users. One example of the direct voice communication services may comprise the “push-to-talk over cellular” (PoC) service also known as the PTT (push-to-talk service). The PoC may be based on Voice over IP (VoIP) technology in cellular networks, such as the GSM/GPRS network.
The direct voice communication services may use capabilities of, for example, the Internet Protocol Multimedia Subsystem (IMS) domain of the core network. The IMS enables IP connections for a communication device and other parties to the communication, such as other communication devices or entities associated with the network. The third generation partnership project (3GPP) has defined use of the GPRS for offering IP connectivity to IMS services.
U.S. patent application Ser. No. 2002/0150091, filed on 17 Apr. 2001, in the name of Lopponen et al., discusses about a packet mode, e.g. IP, group communication service layer provided on top of a standard mainstream cellular network.
Using a service typically requires knowing parameters and/or other information relating to the service. Examples of such parameters may relate to, but are not limited to, parameters of multimedia messaging service (MMS), parameters of application servers, parameters or parameters associated with PoC floor control. These parameters may be, for example, operator specific, server specific, end-user specific or group specific.
A network operator may configure or provide parameters in a communication device. So-called over-the-air (OTA) provisioning may typically be used for providing parameters in activation of a new service or application, at network provisioning, and so on. A non-limiting example may comprise activating a multimedia messaging service in a mobile communication device for the first time and the operator sending operator specific MMS parameters using a short message service (SMS) message. The operator specific MMS parameters may then be stored in a memory of the device automatically, semi-automatically or manually. A communication device may be provided with parameters also, for example, by entering parameters at device manufacturing, entering parameters manually or electronically in a point of sales or using a pre-configured subscriber identity module (SIM) card, and so on. These methods of providing parameters may be suitable for providing a communication device with permanent parameters, or parameters having a long lifetime or being suitable for wide range of service usage.
Parameters for shorter usage, for example relating to only one session, may be negotiated every time when a service session is established or set up. Furthermore, parameters may depend on a network a communication device is currently in contact with or parameters that cannot be specified by the operator. An example of such shorter usage parameters may comprise negotiating speech coding and decoding parameters for a particular connection. A connection device may be configured to negotiate the parameters without user intervention. However, negotiating parameters within the session establishment may add delay to session establishment or set-up procedure, which may lead to weaker end user quality perception.
It is known, that communication devices are able to roam, or in other words to move from a network of one operator, such as a home network, to a network of another operator, such as a visited network. Also, a communication device controlled by one operator may be in connection with one or more communication devices controlled by one or more other operators. Therefore, it may happen, for example, that a communication device is provided with permanent parameters for a service relating to a first operator, but these parameters are not valid for the same service in a network of a second operator. If parameters are unknown, if the parameters are incorrect or if the parameters relate to another server than a serving server, a poor or faulty operation may result and the service may be hard or even impossible to use. Incorrect or missing parameters may result in poor user experience, even if the service works. On the other hand, negotiating parameters in session establishment always when roaming in a visited network, might add significant delays to session establishment. Similarly negotiating parameters always regardless whether in home network or visited network may add significant delays to session establishment.
It shall be appreciated that these issues are not limited to any particular communication environment, but may occur in any appropriate communication system.